Pquest users' meeting summary

Mary, Elmer, Jim, and Jim + PQuest user community:
Thanks for coming to a good solution on the PQuest. Let's hope that a
year from now, or sooner, we're dealing with the initial ramp-up of a
new III-V etcher.
I'd have been there if I wasn't lecturing.
Roger
On 12/1/10 6:39 PM, Mary Tang wrote:
> Dear pquest users --
>>> Many thanks to those who attended and for the contributions by those
> who couldn't. The meeting was well attended (even two faculty!) and
> well-represented by many different groups. Here's a summary:
>>> 1. Chlorine versus fluorine, 2011. Because there are many more
> chlorine than fluorine users, it was decided to increase the
> chlorine-only time. Starting in 2011, the schedule will be 1.5 weeks
> of chlorine-only after chamber clean followed by 0.5 weeks of
> fluorine-allowed. Chamber cleans will be done on alternate Fridays.
> This will keep the current chamber clean frequency, which is good, and
> allow fluorine users access twice/month.
>>> 2. Chlorine versus fluorine, 2010. The system will remain
> chlorine-only until next Friday, Dec. 10, when it becomes
> fluorine-allowed. A chamber clean will be done over the shutdown.
>>> 3. Process problems. Several people have observed variable etch
> rates in ZEP, PMMA, and GaAs. One group's problems seem to be
> recently resolved. Some reminders on pquest operation which will help
> with process control: monitor DC bias voltage (and adjust RF
> accordingly); run O2 clean until DC bias stabilized; check (and rezero
> if needed) the VAT pressure controller; run recipes with chlorine
> flows within controllable range (3 sccm is recommended); use
> ellipsometry to measure resist thicknesses below 1000 A.
>>> 4. Shutdown. Elmer plans to repair the noisy clamp, clean the
> chamber, check for chips in the darkspace, and adjust the clamp
> pressure to try to get the helium blow by down a little. Stray chips
> in the darkspace have been historically known to cause variable etch
> rate or plasma flickering. The clamp pressure is a balancing act
> between good backside cooling and wafer breakage so needs to be done
> carefully.
>>> 5. Other stuff discussed: instituting logsheet data entry on Coral
> disable - this will allow us to collect and monitor data (like DC
> bias); defining a basic process qual, to check machine functionality;
> temperature dots are available to check for substrate heating; optical
> spectroscopy testing for fluorines or chamber cleanliness.
>>> Again, thanks all. We would also like to encourage everyone to share
> observations about pquest process performance, especially any problems
> you encounter.
>>> Team Pquest Etch (Jim and Jimmer, Elmer, Mary)
>